This invention relates to an improved filling machine for filling containers with products containing abrasive materials. More particularly, this invention relates to improved product container holders for filling machines during the filling of such containers.
Many products are filled into the containers in which they are to be sold on high speed filling lines. These lines can fill from about 100 to more than 500 containers a minute. Usually in these filling lines the container will be transported to and from one or more filling stations. Also, a filling station can have a plurality of filling nozzles so that a plurality of containers can be filled at one time. This all requires the coordinated moving of the containers to the filling nozzles, filling and transporting the containers away from the filler nozzles for container sealing and further packaging such as cartoning or shrink wrapping.
One problem that arises on high speed filling lines is that there are misfillings at the filler station. This can be caused by a container not being in alignment with the filler nozzle when the filler nozzle enters the container or the container being defective. If the product is a liquid the mess created is not too great. It also is relatively easy to clean. Gel, paste and powder products create more of a mess, with many of these products also contributing to an increased wear rate for the machine parts. This particularly is the case with bearings, hinge pins, bushings and the like when in contact with a product which contains an abrasive. Such products include toothpastes. Toothpastes by their nature include a particulate abrasive to remove plaque and tartar from teeth. These abrasives include particulate silica, alumina, zeolite, calcium carbonate and phosphates. In a misfill these abrasive containing products get into moving part areas such as bearings, bushings, attaching pins and hinge pins. Such products will increase the wear rate of these parts and require the repair or replacement of these parts at shorter intervals.
This particularly is a problem with dentifrice tube fillers. A common dentifrice tube filler has aluminum tube holder supports, also known as links. The tube holder will fit into, and be supported by, tube holder supports. However, the aluminum tube holders supports experience increased wear and must be repaired and/or replaced at relatively short intervals. This takes a filler out of production for a period of time. This results in lost product production. There also is an increased cost for any repair costs and for the replacement of tube holder supports.
This invention solves the problem of excessive wear of filler equipment parts, and in particular, container holder supports, when used to fill products which contain abrasives. The solution is to use a plastic and preferably a polyurethane plastic, that has a Durometer hardness of more than about 65D and preferably more than about 70D in place of aluminum as the material of the container holder supports. This plastic preferably is used to form the entire container holder support links. The use of links from this plastic in place of aluminum container holder links results in a tube holder link that has a wear rate of 25 to 50% of that of an aluminum tube holder link. Also such links are about 30 to 50 percent of the weight of aluminum links.
The preferred polyurethane links are formed by combining polyurethanes having a Durometer of from about 60D to about 90D to produce a polyurethane having a Durometer of more than about 65D and preferably more than about 70D, and most preferably about 72D. The polyurethane blend is held at pressure in a compression mold for about 15 minutes to 60 minutes, and preferably about 30 minutes. This is followed by a curing in an oven at about 100xc2x0 C. to about 130xc2x0 C., and preferably about 110xc2x0 C. to about 125xc2x0 C. for about 12 to 48 hours, and preferably about 18 to 30 hours. Each container holder support link undergoes this processing to form the polyurethane link having a hardness of more than about 65D and preferably more than about 70D.